Benzoisothiazolinone-1-dioxide derivatives as elastase inhibitors

ABSTRACT

The invention relates to pharmaceutical and cosmetic compositions comprising at least one benzisothiazolinone-1-dioxide derivative with the formula: ##STR1## where R 1  can be hydrogen, and R 2  can be certain generally hydrophobic C 8  -C 20  aliphatic groups or the group: ##STR2## where R 5  is aliphatic or else R 2  is a saturated or unsaturated C 2  -C 6  group ending in an aromatic nucleus. 
     These compositions can be used to inhibit elastases such as human leucocytic elastase. They may be applied topically as a cosmetic. 
     Many of the benzisothiazolinone-1-dioxide derivative specified as active ingredient in such compositions are novel compounds.

FIELD OF THE INVENTION

The present invention relates to benzisothiazolinone-1-dioxide derivatives that can be used as elastase inhibitors, and to compositions containing such inhibitors.

THE RELATED ART

It is well known that elastin is an elastic fibrous protein that occurs in the connective tissues of vertebrates. It is found in the walls of the blood vessels, the skin, lungs, cartilage, ligaments and other tissues. Elastin is the most durable protein in the body, but it suffers a particularly rapid degradation in all the elastin-rich tissues. Such as the vascular walls and the skin, in certain pathological conditions, as well as during the ageing process in general.

Elastin can be attacked only by certain proteases, called elastases or elastase-type proteases. These enzymes include pancreatic elastase and cell elastases, examples of the latter being leucocytic and platelet elastases, as well as the elastases found in macrophages, fibroblasts and the cells of the smooth muscles in the arteries. These enzymes can degrade the elastin in the tissues and organs mentioned above and so contribute to the development of disorders such as arteriosclerosis, emphysema, arthritis and diabetes, as well as to the engaging of the connective tissues in the body.

The activity of elastases is controlled and regulated by natural inhibitors present in the plasma (e.g. α-1-antitrypsin and α-2-macroglobulin) and in secretions from tissues (e.g. the bronchial secretion) [see e.g. W. Hornebeck et al., "Control of elastic tissue destruction by elastase inhibitors", in Deyl and Adam (eds.), Connective Tissue Research: Chemistry, Biology and Physiology, pp. 233-246, A. R. Liss Inc., New York, 1981]. Furthermore, numerous bacteria capable of entering the body secrete elastolytic proteases whose action greatly contributes to the pathogenic activity of these microorganisms.

It is also known that the growth of malignant tumors such as carcinomas and sarcomas, and the formation of metastases, which are often fatal to the patient, are also affected by the secretion of elastase-type proteases [see for example W. Hornebeck, D. Brechemier, G. Bellon, J. J. Adnet and L. Robert, "Biological Significance of Elastase-like Enzymes in Arteriosclerosis and Human Breast Cancer", in P. Straulli, A. J. Barrett and A. Baici (eds.), Proteinases and Tumor Invasion, vol. 6, ORTC Monograph Series, pp. 117-141, Raven Press, New York, 1980]. These enzymes can destroy the surrounding tissues and thus enable the malignant cells to enter the blood circulation, as a result of which the tumor can invade the body.

For all these reasons, it is important to possess inhibitors that can control the activity of elastases.

However, some elastases are useful or even indispensable for the body, for example when they digest the bacteria that have been destroyed by the phagocytic action of macrophages. It is therefore important to possess elastase inhibitors that act selectively in the elastic fibres whose integrity is indispensable for the proper functioning of the body.

The fact is that the enzymatic hydrolysis of elastin by elastases can be seen as a decisive factor in numerous disorders of the elastic tissues, such as arteriosclerosis, emphysema and certain skin diseases. In the living body, this proteolysis occurs when the balance is upset between the level of proteases with an elastolytic action and the level of natural inhibitors originating in the plasma or the tissues. One method proposed for the treatment of a genetic of functional deficiency of these protease inhibitors is to introduce natural inhibitors such as α-1-antitrypsin as a replacement therapy.

However, the use of natural inhibitors has numerous disadvantages, including the cost of the treatment and the risk of adverse immunological reactions. Furthermore, the elastase inhibitors used in the experimental treatment of animals with emphysema are highly toxic.

Synthetic elastase-inhibitors have therefore been under investigation for some years now. Thus, U.S. Patent Specification U.S. Pat. No. 4,195,023 describes the use of 2-benzisothiazol-3-one derivatives and saccharin derivatives to inhibit elastases. The preferred compounds in that publication are derivatives substituted with a furoyl or a thenoyl group. The publication also gives some data for 2-(2-ethylbutyryl)-saccharin and 2-acryloylsaccharin. According to this document, the alkyl chain of the derivative contains at most 10 carbon atoms and is preferably branched, but the only example illustrated has a hydrocarbon chain with no more than five carbon atoms.

Although these inhibitors give satisfactory results, they are not sufficiently specific for the elastic fibres.

European Patent Specification EP-A 0 126.009 describes some peptide derivatives that can be used as elastase inhibitors and are specific for elastic fibres. These derivatives are lipopeptides with a hydrophobic acyl group and a special peptide chain. However, these lipopeptides, which are consequently bifunctional, have the major disadvantage of containing a peptide moiety, which is susceptible to hydrolysis by other proteinases.

The aim of the present invention is therefore to incorporate into pharmaceutical or cosmetic compositions elastase inhibitors in the form of bifunctional benzisothiazolinone-1-dioxide derivatives with a) a hydrophobic chain that has an affinity for elastin and b) a moiety that is not a peptide group (so that it is more resistant to enzymatic hydrolysis) and which can also acylate the active serine in the elastase.

SUMMARY OF THE INVENTION

The present invention therefore provides a composition comprising (i) an elastase inhibitor which is at least one benzisothioazolinone-1-dioxide derivative having the formula: ##STR3## where R¹ is a hydrogen atom or a C₁ -C₅ alkyl or alkoxy group, and

R² is a monovalent C₈ -C₂₀ alkyl or C₉ -C₂₀ alkenyl group, optionally substituted with OH or COOH group,

R² is a group with the formula: ##STR4## where R³ is a divalent straight or branched C₂ -C₆ saturated or ethylenically unsaturated aliphatic group ##STR5## is an aromatic nucleus R⁴ is OH, a C₁ -C₄ alkyl or a C₁ -C₄ alkoxy group

n is zero or an integer in the range of 1-5, and when n>1, the R⁴ groups can be different, or else

R² is a group with the formula: ##STR6## where R¹ is the same as above, and

R⁵ is a divalent straight or branched C₈ -C₂₀ saturated or ethylenically unsaturated aliphatic group,

and (ii) a pharmaceutically or cosmetically acceptable carrier or vehicle.

DETAILED DESCRIPTION

A benzisothiazolinone-1-dioxide derivative of formula (I) above, which is the active ingredient of a composition as above, has two functional groups, namely a "lipid arm" (R² or part of R²), which has a high affinity for the elastic fibres in question, and the benzisothiazolinone-1-dioxide moiety, which can react with elastase in order to inhibit it.

Owing to the presence of this hydrophobic chain, the benzisothiazolinone-1-dioxide derivatives of the present invention can accumulate on the elastic fibres to be protected and therefore act exclusively or almost exclusively on the elastase located near these fibres. In view of this mode of action, it is possible to make the substance act specifically at the site of the target fibres to be protected, which ensures a more efficient inhibition of elastase.

The compounds according to the invention are therefore more efficient and more economical bifunctional inhibitors than the known synthetic inhibitors, which lack the functional group that has a special affinity for the elastic fibres present in the tissues to be protected.

The acylsaccharins described in U.S. Pat. No. 4,195,023, which have the formula: ##STR7## carry a hydrocarbon chain A with generally at most five carbon atoms, and this is not long enough to confer on the derivative either an affinity for elastin or an ability to occupy the hydrophobic site on elastase. As will be seen later, the affinity of the derivative for elastin and for the hydrophobic site on the elastase does not become detectable until the number of carbon atoms reaches nine, improving as the number reaches eleven and peaking when this number is 16.

As mentioned in the definition of the compounds according to the invention given above, a monovalent C₈ -C₂₀ straight-chain or branched alkyl group can carry at least one substituent in the form of an OH or COOH group. If the monovalent alkyl is not substituted with these groups, it preferably contains 11 carbon atoms. Such examples of such alkyl groups include the nonyl, undecyl, tridecyl, pentadecyl, heptadecyl and nonadecyl groups, while COOH--(CH₂)₈ -- is an example of the substituted alkyl groups.

A monovalent C₉ -C₂₀ alkenyl group is a monovalent alkylene group theoretically obtainable by removing a hydrogen atom from a carbon in an olefinic hydrocarbon. Such a group may contain a single ethylenic double bond or more than one ethylenic double bond. As before, these groups may be either unsubstituted or they may carry at least one OH or COOH group. Examples of such unsaturated groups are the dec-9-enyl, hepatadec-8-enyl, hepadeca-8,11-dienyl and the CH₃ --(CH₂)₅ --CHOH--CH₂ --CH═CH--(CH₂)₇ -- group.

A divalent group R³ may in particular be a group theoretically obtainable by removing hydrogen from each of two terminal carbons in a straight-chain or branched alkane or alkene, examples being the --CH═CH-- group, the --CH₂ --CH₂ -- group and the --(CH₂)₃ -- group.

An aromatic nucleus, denoted ##STR8## may comprise one or more benzene rings, examples being the groups obtained from benzene, anthracene, naphthalene, biphenyl, terphenyl, triphenylbenzene, indene, diphenylene, fluorene and phenanthrene.

A divalent group R⁵ may in particular be a group theoretically obtainable by removing a hydrogen atom from each of two terminal carbons in a straight-chain or branched C₈ -C₂₀ alkane, alkene or polyalkene, as exemplified by the --(CH₂)₈ --group.

Furthermore, R¹ can be a hydrogen atom or a substituent chosen from amongst C₁ -C₅ alkoxy groups. When R¹ is a substituent, it is desirably chosen such as to promote the hydrolytic opening of the heterocyclic ring. However, R¹ is generally a hydrogen atom.

As mentioned before, R² is the functional group that confers an affinity for the elastic fibres on the compound of the invention, owing to its lipophilic nature.

In the first embodiment of the invention, R² is a long-chain alkyl or alkenyl group whose long hydrocarbon chain confers a strongly lipophilic nature on the compound according to the invention. This facilitates its penetration into the skin and makes it suitable for cosmetic use.

In the second embodiment of the invention, R² is a group with the formula: ##STR9## where R³ and R⁴ are as defined before;

R³ is preferably a divalent group obtained from an alkane ##STR10## is a benzene ring R⁴ is a C₁ -C₄ alkoxy group or a hydroxyl group, and

n is 1 or 2.

These R² groups are exemplified by the 3,4-dimethoxycinnamoyl, cinnamoyl, dihydrocinnamoyl and p-methoxyphenylbutyryl radical.

In the second embodiment, the compound according to the invention is again lipophilic, this time because it comprises an aromatic nucleus.

In the third embodiment of the invention, R² has the following formula: ##STR11## where R¹ and R⁵ are as defined before, but;

R¹ is preferably a hydrogen atom, and

R⁵ is a divalent group obtained from an alkane.

In this case, this R⁵ group confers on the compound both a lipophilic character and an affinity for the elastic fibres in question, while the presence of two benzisothiazolinone-1-dioxide rings increases the inhibitory activity.

The benzisothiazolinone-1-dioxide derivatives of this invention can be prepared by conventional methods in which the starting materials are an acid chloride and an alkali metal derivative of the corresponding benzisothiazolinone-1-dioxide.

Thus, it is possible to prepare the benzisothiazolinone-1-dioxide derivative of the invention, with the formula: ##STR12## where R¹ is a hydrogen atom or a C₁ -C₅ alkyl or alkoxy group,

R² is an optionally substituted monovalent C₉ -C₂₀ alkyl or alkenyl group,

R² is a group with the formula: ##STR13## all as defined before by reacting an alkali metal derivative of benzisothiazolinone-1-dioxide having the formula: ##STR14## where R¹ is as defined before, and M is an alkali metal with an acid chloride having the formula:

    R.sup.2 --COCL                                             (V)

wherein R² is the same as before.

The benzisothiazolinone-1-dioxide derivative with formula I in which R¹ is as defined above and R² represents the group with formula (III) ##STR15## where R¹ and R⁵ are as defined before can be prepared by reacting an alkali metal derivative of a benzisothiazolinone-1-dioxide having formula (IV) with an acid chloride represented by:

    CLCO--R.sup.5 --COOH                                       (VI)

where R⁵ is as defined before, the alkali metal being preferably sodium, but potassium can also be used.

The reaction between the alkali metal derivative and the acid chloride can be carried out in both cases by refluxing the alkali metal derivative of the benzisothiazolinone-1-dioxide (IV) with the acid chloride (V) or (VI) in a suitable solvent such as tetrahydrofuran, with stirring. The product formed can then be isolated by filtration and purified by recrystallization from a suitable solvent such as ethanol.

When an acid chloride with formula (VI) is used, the reaction leads to two different products (VII) and (VIII): ##STR16## which can be separated from each other by high-pressure liquid chromatography.

The present invention also relates to the new benzisothiazolinone-1-dioxide derivatives themselves with the formula: ##STR17## where R¹ is a hydrogen atom or a C₁ -C₅ alkyl or alkoxy group, and

R² is a monovalent C₈ -C₂₀ alkyl or C₉ -C₂₀ alkenyl group optionally substituted with at least one OH or COOH group, with the proviso that if R² is unsubstituted alkyl it is C₁₁ -C₂₀ alkyl, or

R² is a group with the formula: ##STR18## where R³ is a divalent straight or branched C₂ -C₆ aliphatic group ##STR19## is an aromatic nucleus R⁴ is OH, a C₁ -C₄ alkyl group or a C₁ -C₄ alkoxy group

n is zero or an integer in the range of 1-5, and when n>1, the R⁴ groups can be different, or else

R² is a group with the formula: ##STR20## where R¹ is as defined before and R⁵ is a divalent straight or branched C₈ -C₂₀ aliphatic group.

This invention also embraces methods of treatment comprising administration of compositions of this invention as specified above, especially cosmetic treatment by topical application.

The pharmaceutical compositions of this invention may be solutions, suspensions, emulsions, ointments, creams, powders, lotions or gels, with non-toxic carriers or vehicles and possibly also additives and excipients.

The compounds of the invention can thus be incorporated in conventional excipients such as polyethylene glycols, waxes, fats, stearic substances, talc, alcohols, vegetable oils (e.g. sweet or expressed almond oil), mineral oils, wetting agents, thickeners, preservatives, perfumes and colorants.

These pharmaceutical compositions are intended for oral, parenteral, and--most often--local or topical administration.

These compositions can be used to treat or prevent any undesirable biological or pathological change caused by elastase, such as:

the degradation of the cutaneous elastic fibres due to ageing or to exposure to the sun

lysis of the pulmonary elastic fibres due to smoking, ageing and various disorders

emphysema

the progressive lysis of the elastic layers in the arterial walls during the development of arteriosclerosis

arterial disorders due to ageing

inflammatory foci

destruction of tissues (e.g. ulcers and necrosis)

periodontal disorders (degeneration of the gum)

certain disorders of the bones and joints

the growth of tumours and the formation of metastases.

As mentioned before, the compounds of the invention can also be used as cosmetics intended to counteract the undesirable effects of elastase on the skin, such as ageing. These cosmetics are essentially intended for application to the skin and can be e.g. solutions, emulsions, creams, ointments, powders, lotions, gels, soaps, milks, face packs, aerosols or bath oils. In the case of emulsions, it is best to use the water-in-oil type, containing the compound of the invention solubilized in the oil phase. These compositions can be prepared by the conventional methods, using the carriers, excipients and additives normally incorporated in such compositions.

The concentration of the new derivative (I) in the composition is chosen according to its activity and the effect required. When intended for local administration once or twice a day, the composition can contain the compound of the invention in a concentration of 0.1 to 5 wt-%.

The cosmetic and pharmaceutical compositions according to the invention that are intended for local application may also contain penetration enhancers or penetration potentiators, which can raise the beneficial effect of the elastase inhibitor by improving its diffusion through the epidermis until it reaches its site of action in the stratum corneum.

These penetration enhancers can act in different ways. For example, they can improve the distribution of the elastase inhibitor on the surface of the skin. Alternatively, they can improve its distribution in the skin after local application, thus promoting the migration of the elastase inhibitor within the stratum corneum. The penetration enhancers may also raise the efficiency of the elastase inhibitor by other mechanisms.

Consequently, the pharmaceutical and cosmetic compositions according to the invention can optionally comprise up to 30 wt-% and preferably 0.1-25 wt-% of a penetration enhancer, examples of which are listed below.

2-methylpropanol-2

2-propanol

ethyl 2-hydroxypropanoate

ethyl polyoxyethylene hexane-2,5-diol ether

di-(2-hydroxypropyl) ether

pentane-2,4-diol

acetone

methyl polyoxyethylene ether

2-hydroxypropionic acid

2-hydroxyoctanoic acid

1-propanol

1,4-dioxan

tetrahydrofuran

1,4-butanediol

propylene glycol dipelargonate

polyoxypropylene 15-stearyl ether

octanol

polyoxyethylene ester of oleyl alcohol

dioctyl adipate

dicapryl adipate

diisopropyl adipate

diisopropyl sebacate

dibutyl sebacate

diethyl sebacate

dimethyl sebacate

dioctyl sebacate

dibutyl suberate

dioctyl azeleate

dibenzyl sebacate

dibutyl phthalate

dibutyl azeleate

ethyl myristate

dimethyl azeleate

butyl myristate

urea

diethyl-m-toluamide

1-dodecylazacycloheptan-2-one

dibutyl succinate

dodecyl phthalate

decyl oleate

ethyl caproate

ethyl salicylate

isopropyl palmitate

ethyl laurate

2-ethylhexyl pelargonate

isopropyl isostearate

butyl laurate

benzyl benzoate

butyl benzoate

hexyl laurate

ethyl caprate

ethyl caprylate

butyl stearate

benzyl salicylate

2-hydroxypropanoic acid

2-hydroxyoctanoic acid.

Other substances that promote the penetration of the active ingredient into the skin include the esters of pyroglutamic acid having the formula: ##STR21## where R is either a C₁ -C₃₀ alkyl group or it is the group: ##STR22## where T' and T" (which may be identical or different) represent a hydrogen atom or the following group:

    [(CH.sub.3).sub.u.(CH.sub.2 OH).sub.v.(CH.sub.2).sub.w.(CH.sub.3 CH.sub.2).sub.x.(CHOH).sub.y.(CH═CH).sub.I ]-

where

u is zero or 1

v is zero, 1 or 2

w is zero or an integer in the range of 1-21

x is zero or an integer in the range of 1-4

y is zero, 1 or 2

z is zero or an integer in the range of 1-22 and

u+v+w+x+y+z is an integer in the range of 1-22, but when the CH═CH group is present, the total number of carbon atoms in the above group is 10-22.

The following compounds are suitable examples of pyroglutamic acid esters in which the R group, featuring in formula (IX), is a C₁ -C₃₀ alkyl group:

methyl pyroglutamate

ethyl pyroglutamate

n-propyl pyroglutamate

n-butyl pyroglutamate

n-heptyl pyroglutamate

n-octyl pyroglutamate

n-nonyl pyroglutamate

n-decyl pyroglutamate

n-undecyl pyroglutamate

n-dodecyl pyroglutamate

n-tridecyl pyroglutamate

n-tetradecyl pyroglutamate

n-hexadecyl pyroglutamate

n-octadecyl pyroglutamate

n-eicosyl pyroglutamate

isopropyl pyroglutamate

2-methylhexyl pyroglutamate

2-ethylhexyl pyroglutamate

3,7-dimethyloctyl pyroglutamate

2-hexyldecyl pyroglutamate

2-octyldodecyl pyroglutamate

2,4,4-trimethyl-1-pentyl pyroglutamate and

methyloctyl pyroglutamate.

The preferred esters are those in which R is a straight-chain or branched alkyl group with 1-14 and preferably 1-6 carbon atoms. Other preferred examples of pyroglutamic acid esters are those in which R represents the group: ##STR23## where the symbols T' and T" stand for the group:

    [(CH.sub.3).sub.u.(CH.sub.2 OH).sub.v.(CH.sub.2).sub.w.(CH.sub.3 CH.sub.2).sub.x.(CHOH).sub.y.(CH═CH).sub.x ].sup.-

and which comprise saturated or unsaturated straight-chain or branched C₁ -C₂₂ aliphatic groups such as the alkyl groups: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, n-valeryl, isovaleryl, n-carproyl, n-heptyl, n-caprylyl, n-capryl, lauryl, myristyl, palmityl, stearyl and arachidyl group, and the C₁₀ -C₂₂ alkenyl groups: linoleyl, linolenyl, γ-linolenyl, arachidonyl and columbinyl group.

Other examples of these groups comprise hydroxyalkyl radicals with 1-22 carbon atoms, such as the hydroxymethyl, 2-hydroxyethyl, 2-hydroxy-n-propyl, 3-hydroxy-n-propyl, 2-hydroxy-n-butyl, 3-hydroxy-n-butyl, 4-hydroxyl-n-butyl, 5-hydroxy-n-valeryl, 6-hydroxy-n-caproyl, 2,3-dihydroxy-n-propyl, 2,3-dihydroxy-n-butyl and 12-hydroxystearyl group.

This list is not exhaustive, and other alkyl or substituted alkyl groups can be added to it as further examples of T' and T".

Other specific examples of pyroglutamic acid esters that are particularly suitable for use as penetration enhancers are as follows:

2-(pyroglutamoyloxy)-propionic acid

methyl 2-(pyroglutamoyloxy)-acetate

ethyl 2-(pyroglutamoyloxy)-n-propionate

ethyl 2-(pyroglutamoyloxy)-n-butyrate

ethyl 2-(pyroglutamoyloxy)-isobutyrate

ethyl 2-(pyroglutamoyloxy)-n-valerate

ethyl 2-(pyroglutamoyloxy)-n-caproate

ethyl 2-(pyroglutamoyloxy)-n-heptylate

ethyl 2-(pyroglutamoyloxy)-n-caprylate

ethyl 2-(pyroglutamoyloxy)-n-pelargonate

ethyl 2-(pyroglutamoyloxy)-3-hydroxybutyrate

isopropyl 2-(pyroglutamoyloxy)-n-propionate

isopropyl 2-(pyroglutamoyloxy)-n-caprylate

n-propyl 2-(pyroglutamoyloxy)-n-propionate

n-propyl 2-(pyroglutamoyloxy)-n-caprylate

stearyl 2-(pyroglutamoyloxy)-n-propionate

12-hydroxystearyl 2-(pyroglutamoyloxy)-n-propionate

stearyl 2-(pyroglutamoyloxy)-n-stearate

palmityl 2-(pyroglutamoyloxy)-n-propionate

linoleyl 2-(pyroglutamoyloxy)-n-propionate

linoleyl 2-(pyroglutamoyloxy)-n-caprylate

lauryl 2-(pyroglutamoyloxy)-n-caprylate

stearyl 2-(pyroglutamoyloxy)-n-caprylate

glyceryl mono-2-(pyroglutamoyloxy)-n-propionate

glyceryl mono-2-(pyroglutamoyloxy)-n-caprylate, and

glyceryl di-2-(pyroglutamoyloxy)-n-propionate.

These lists of specific examples of pyroglutamic acid esters are not exhaustive, and many other examples with the overall structure of these esters could be mentioned.

Other examples of penetration enhancers are as follows:

dimethylsulphoxide

N,N-dimethylacetamide

N,N-dimethylformamide

2-pyrrolidone

1-methyl-2-pyrrolidone

5-methyl-2-pyrrolidone

1,5-dimethyl-2-pyrrolidone

1-ethyl-2-pyrrolidone

phosphine oxides

sugar esters, and

tetrahydrofurfuryl alcohol.

Other features and advantages of the present invention will emerge from the following non-limitative examples, given here to illustrate the present invention.

EXAMPLE 1 Preparation of 2-lauroylbenzisothiazolinone-1-dioxide

21.8 g (0.1 mole) of lauroyl chloride and 22.66 g (0.11 mole) of dry sodium benzisothiazolinone-1-dioxide were refluxed for 4 h in 80 ml of tetrahydrofuran, with mechanical stirring. The reaction mixture was filtered, the filtrate was concentrated under vacuum, and the product was recrystallized from ethanol and dried in air. This gave 30 g of 2-lauroylbenzisothiazolinone-1-dioxide (m.p. 85° C.).

EXAMPLES 2-6

The method described in Example 1 was used to prepare various compounds with formula I, in which the groups denoted by R¹ and R² are shown in Table 1. The acid chloride used here was myristoyl chloride in Example 2, palmitoyl chloride in Example 3, stearoyl chloride in Example 4, decanoyl chloride in Example 5 and undecenoyl chloride in Example 6. The melting points of the compounds obtained are given in Table 1.

EXAMPLE 7 Preparation of 2-[(3,4)-dimethoxycinnamoyl]-benzisothiazolinone-1-dioxide

227 g (0.1 mole) of 1,4-dimethoxycinnamoyl chloride and 22.66 g (0.11 mole) of anhydrous sodium benzisothiazolinone-1-dioxide were refluxed for 5 h in 150 ml of dry tetrahydrofuran, with mechanical stirring. The reaction mixture was then filtered, the filtrate was concentrated under vacuum, and the product obtained was recrystallized from ethanol, giving 22 g of 2-[(3,4)-dimethoxycinnamoyl]-benzisothiazolinone-1-dioxide (m.p. 171° C.).

EXAMPLES 8-10

The method described in Example 7 was used to prepare various compounds with formula I, in which the groups denoted by R¹ and R² are shown in Table 1. The acid chloride used here was cinnamoyl chloride in Example 8, dihydrocinnamoyl chloride in Example 9, and p-methoxyphenylbutyryl chloride in Example 10. The melting points of the compounds obtained are given in Table 1.

EXAMPLE 11 Preparation of compounds (VIIa) and (VIIIA): 1,10-decanedioyl-bis-(2-benzisothiazolin-3-oxo-1,1-dioxide and 1-carboxynonanoyl-10-(2-benzisothiazolin-3-oxo-1,1-dioxide) ##STR24##

A mixture of 9 g (0.05 mole) of sebacoyl chloride and 20.6 g (0.1 mole) of sodium benzisothiazolinone-1-dioxide was refluxed for 4 h. The reaction mixture was then filtered, and the filtrate was concentrated under vacuum. The resulting compounds VIIa and VIIIa were separated by preparative high-pressure liquid chromatography, using a reversed-phase C18 column and a water/acetonitrile gradient. The R_(f) value of compounds (VIIa) and (VIIIa) was respectively 0.8 and 0.2 when eluted on silica with a 99:1 chloroform-methanol mixture (by volume).

Both the mixture of compounds VIIa and VIIIa and each of them separately can be used as an elastase inhibitor.

EXAMPLE 12 Inhibition of human leucocytic elastase

The inhibition test was carried out by using succinyltrialanine p-nitroanilide as a synthetic substrate. Human leucocytic elastase, used at a concentration of 1 μg/ml, was first pre-incubated for 15 min with the compounds of the invention, used at a concentration of 0.5, 5, 10, 25 and 50 μg/ml. These compounds were added in the form of a solution in acetone, the final acetone concentration of the reaction mixture being 1%.

The degree of hydrolysis of the substrate was determined by measuring the amount of p-nitroaniline released, using a Philips PO 8700 spectrophotometer at 410 nm. The 50% inhibitory concentration (IC₅₀) in mole/liter was then determined by a graphical method, using the inhibition values obtained with the different concentrations of the substrate and the inhibitor. Table 1 shows the IC₅₀ values obtained for the compounds of the invention prepared in Examples 1-5. It can thus be seen that the inhibitory action of these compounds increases with the number of carbon atoms in the R² group on going from C₉ to C₁₇.

                  TABLE 1                                                          ______________________________________                                         Example                        M.p.,                                           No.    R.sup.1                                                                              R.sup.2           °C.                                                                          IC.sub.50, mole/l                          ______________________________________                                         1      H     C.sub.11 H.sub.23 85   1.1 × 10.sup.-5                      2      H     C.sub.13 H.sub.27 89   9.2 × 10.sup.-6                      3      H     C.sub.15 H.sub.31 94   2.1 × 10.sup.-6                      4      H     C.sub.17 H.sub.35 90   4.7 × 10.sup.-6                      5      H      C.sub.9 H.sub.19 84   8.6 × 10.sup.-5                      6      H     C.sub.10 H.sub.19 75   7.5 × 10.sup.-5                      7      H                                                                                     ##STR25##        171    5 × 10.sup.-6                      8      H                                                                                     ##STR26##        222    9 × 10.sup.-5                      9      H                                                                                     ##STR27##        142  4.8 × 10.sup.-5                      10     H                                                                                     ##STR28##        142  3.6 × 10.sup.-5                      ______________________________________                                    

EXAMPLE 13 Protective action of 2-lauroylbenzisothiazolinone-1-dioxide on elastin and its inhibition of human leucocytic elastase

Three series of tests were carried out here to illustrate the manner by which the compound prepared in Example 1 inhibits the elastase.

1) Inhibitory action

The elastase, used in a concentration of 1 μg/ml, was incubated for 10 min with different amounts of 2-lauroylbenzisothiazolinone-1-dioxide in a 100-mM tris-HCl buffer (pH 8.4) containing 0.01% of Brij 35 and 0.01% of NaN₃. Tritiated insoluble elastin extracted from the nuchal ligament was then added in a concentration of 75 μg/ml, corresponding to a radioactivity level of 2.2×10⁶ counts per minute (cpm) per ml.

2) Protective action

The substances and concentrations were the same as above, but the insoluble elastin was incubated with 2-lauroylbenzisothiazolinone-1-dioxide for 30 min before the introduction of human leucocytic elastase.

3) Third series

Again the same substances and concentrations were used as before, but the insoluble elastin was first incubated with 2-lauroylbenzisothiazolinone-1-dioxide for 10 min. The mixture was then centrifuged, the supernatant was discarded, and the residue was suspended in the buffer that contained human leucocytic elastase.

The degree of the hydrolysis of elastin was calculated in all three cases after incubation with elastase for 7 h at 37° C. by determining the radioactivity in the solubilized peptides derived from the elastin.

The aim of the first series was to determine the direct ability of 2-lauroylbenzisothiazolinone-1-dioxide to inhibit the activity of human leucocytic elastase. The results show that, when used in a concentration of 45 μg/ml, 2-lauroylbenzisothiazolinone-1-dioxide inhibits the elastin-cleaving activity of human leucocytic elastase by 80%, the value of IC₅₀ being 7.5×10⁻⁵ M.

The second and third series of investigations showed that the compound of the invention also protects the insoluble elastic fibres from the action of human leucocytic elastase with a maximum inhibition of 50% when used in a concentration of 50-100 μg/ml, the IC₅₀ value being 1.3-2.9×10⁻⁴ M.

EXAMPLE 14 Protective action of 2-lauroylbenzoisothiazolinone-1-dioxide on the elastin in rabbit skin

Frozen biopsy specimens of rabbit skin having a thickness of 6μ were treated either with human leucocytic elastase in a concentration of 15 μg/ml or with a mixture of this and 2-lauroylbenzisothiazolinone-1-dioxide, prepared in Example 1 and used in a concentration of 350 μg/ml.

The segments of rabbit skin were incubated for 1.5 h at 37° C. In the control experiment, they were incubated only with the buffer (100-mM tris-HCl, 0.1% of Brij 35, pH 8) under the same conditions.

Thin sections of the skin specimens were then fixed for 2 min in 95% ethanol and stained for 3 h by a modified Verhoeff method, described by Godeau et al. [cf. Pathol. Biol., 32 (1984) pp. 215-6]. After a suitable contrast treatment, the surface density of the elastic fibres was determined by automatic image analysis, carried out directly on the microscope slides.

In the absence of elastase, the volume fraction V occupied by the cutaneous elastic fibres was 6.25±0.5%. After treatment with human leucocytic elastase, this value was only 4.1±0.8%. When the elastase was first incubated with 2-lauroylbenzisothiazolinone-1-dioxide, however, the value of V was 6.00±1%, which indicates a virtually complete (96%) protection from the action of elastase.

EXAMPLE 15 Determination of the inhibition of other serine-containing proteases

The inhibition exerted by the following two compounds on serine-containing proteases other than human Teucocytic elastase was determined in this Example:

2-butyryl-benzisothiazolinone-1-dioxide (B) and

2-palmitoyl-2-benzisothiazolinone-1-dioxide (P).

More specifically, the activity of a) pig pancreatic elastase, b) trypsin, c) thrombin and d) plasmin was determined in the presence of these inhibitors and of the synthetic substrates: a) succinyltrialanine p-nitroanilide, b) N-benzoyl-DL-arginine p-nitroanilide, c) N-p-tosyl-gly-pro-arg p-nitroanilide and d) N-p-tosyl-gly-pro-lys p-nitroanilide, respectively.

Each enzyme was first incubated for 15 min with 0-50 μg/ml of compound B or P mentioned above, which had been dissolved in acetone as in the test with human leucocytic elastase, the final concentration of this solvent in the reaction mixture being 1%.

The appropriate substrate was then added to each enzyme, and its hydrolysis was monitored with a Philips 8700 spectrophotometer at 410 nm by measuring the amount of p-nitroaniline appearing in the medium.

The results were used to plot the inhibition of the enzymatic activity against the amount of inhibitor present in the medium. These curves were then used to find the median inhibitory concentration (IC₅₀) in mole/l, which inhibits 50% of the enzymatic activity.

Inhibition of human leucocytic elastase was also determined, as in Example 12.

To be able to compare the inhibitory power of the compounds tested on the various enzymes used, the E/IC₅₀ value was calculated, where E is the concentration of the enzyme in the reaction mixture (also expressed in mole/l ). The higher the value of this quotient, the stronger the inhibitory activity, and therefore the lower the number of moles of the inhibitor that are needed to obtain a 50% inhibition for the same number of moles of the enzyme.

The results listed in Table 2 show that palmitoylbenzisothiazolinone-1-dioxide is a better inhibitor than butyrylbenzisothiazolinone-1-dioxide, irrespective of the enzyme used. Furthermore, these inhibitors show different specificities for the different serine proteases employed. Thus, 2-butyrylbenzisothiazolinone-1-dioxide inhibits human leucocytic elastase and pig pancreatic elastase more strongly than it inhibits thrombin; it has no effect on plasmin and in fact activates trypsin. 2-Palmitoyl-2-benzisothiazolinone-1-dioxide inhibits human leucocytic elastase, pig pancreatic elastase and trypsin 20-40 times as strongly as it inhibits thrombin. This indicates that the compound according to the invention, i.e. 2-palmitoyl-benzisothiazolinone-1-dioxide, is much more efficient than 2-butyrylbenzisothiazolinone-1-dioxide, in which the hydrocarbon chain contains fewer than nine carbon atoms.

                  TABLE 2                                                          ______________________________________                                                       E/IC.sub.50                                                                    Butyrylbenziso-                                                                          Palmitoylbenziso-                                                    thiazolinone-                                                                            thiazolinone-                                                        1-dioxide 1-dioxide                                              ______________________________________                                         Human leucocytic elastase                                                                        7 × 10.sup.-4                                                                      8.1 × 10.sup.-3                              Pig pancreatic elastase                                                                        3.7 × 10.sup.-6                                                                      3.2 × 10.sup.-3                              Trypsin         activator   4.2 × 10.sup.-3                              Thrombin        2.3 × 10.sup.-6                                                                      1.8 × 10.sup.-4                              Plasmin         inactive                                                       ______________________________________                                    

Examples 16-21 illustrate some cosmetic compositions containing elastase inhibitors according to the present invention.

EXAMPLE 16

This Example illustrates a gel for the treatment of hair, this product containing the compound mentioned in Example 2, i.e. 2-myristoylbenzisothiazolinone-1-dioxide, and having the following composition.

    ______________________________________                                                         Amount, wt-%                                                   ______________________________________                                         Emulsifier        20.00                                                        Silicone oil      20.00                                                        Inhibitor from Example 2                                                                          2.00                                                        Sodium hydroxide   4.55                                                        1,3-Butanediol    11.00                                                        Lactic acid        5.00                                                        Water             37.45                                                                          100.00                                                       ______________________________________                                    

EXAMPLE 17

This Example illustrates a face pack containing the inhibitor used in Example 4, i.e. 2-stearoylbenzisothiazolinone-1-dioxide, and having the following composition, the product being prepared by mixing the ingredients together.

    ______________________________________                                                           Amount, %                                                    ______________________________________                                         Kaolin              35.00                                                      Bentonite           5.00                                                       Cetyl alcohol       2.00                                                       Potassium dodecyl sulphate                                                                         1.00                                                       Glycerol            10.00                                                      Nipagin M           0.10                                                       Inhibitor from Example 4                                                                           5.00                                                       Perfume             5.00                                                       Water               36.90                                                                          100.00                                                     ______________________________________                                    

EXAMPLE 18

This Example illustrates a lotion suitable for the treatment of nails, containing the inhibitor used in Example 6, i.e. 2-undecenoylbenzisothiazolinone-1-dioxide, and having the following composition, the lotion (which had a pH of 4.4) being prepared by homogenizing the mixture of its ingredients.

    ______________________________________                                                          Amount, %                                                     ______________________________________                                         Inhibitor from Example 6                                                                          6.00                                                        Sodium hydroxide   1.50                                                        Ethanol            10.00                                                       1,2-Propanediol    55.00                                                       Water              27.50                                                                          100.00                                                      ______________________________________                                    

EXAMPLE 19

This Example illustrates a skin cream formed by a water-in-oil emulsion and containing the inhibitor from Example 1, i.e. 2-lauroylbenzisothiazolinone-1-dioxide in its continuous oil phase, the composition of the cream being as follows.

    ______________________________________                                                         Amount, wt-%                                                   ______________________________________                                         Silicones         24.00                                                        Sodium chloride   2.00                                                         Inhibitor from Example 1                                                                         3.00                                                         Lactic acid       5.00                                                         Humectants        5.00                                                         Bleaching agent   0.15                                                         Preservatives     0.05                                                         Oil of evening primrose                                                                          3.00                                                         Sunscreens        4.00                                                         Bactericides      0.30                                                         Water             53.50                                                                          100.00                                                       ______________________________________                                    

This skin cream, which had a pH of 4, was prepared by mixing the silicones, the bleaching agent and the preservatives together, adding a mixture of the other ingredients in small portions, and homogenizing the product.

EXAMPLE 20

This Example illustrates a water-in-oil type cream, which contained sunscreens in its continuous oil phase, together with the inhibitor from Example 7, i.e. 2-(3,4-dimethyoxycinnamoyl)-benzisothiazolinone-1-dioxide. This cream had the following composition.

    ______________________________________                                                          Amount, %                                                     ______________________________________                                         Silicones          24.00                                                       Humectants         10.00                                                       Bleaching agent    0.15                                                        Preservatives      0.05                                                        Oil of evening primrose                                                                           3.00                                                        Sunscreens         4.00                                                        Bactericides       0.30                                                        Inhibitor from Example 7                                                                          1.00                                                        Ammonium hydroxide 2.00                                                        Ammonium chloride  2.00                                                        Lactic acid        5.00                                                        Water              48.50                                                                          100.00                                                      ______________________________________                                    

EXAMPLE 21

This Example illustrates a water-in-oil type cream that contained sunscreens in its continuous oil phase, together with the inhibitor with formula (VIIa) from Example 11, i.e. 1,10-decanedioyl-bis-(benzisothiazolin-3-oxo-1,1-dioxide), the cream having the following composition.

    ______________________________________                                                         Amount, %                                                      ______________________________________                                         Silicones         24.00                                                        Humectants        10.00                                                        Bleaching agent   0.15                                                         Preservatives     0.05                                                         Oil of evening primrose                                                                          3.00                                                         Sunscreens        4.00                                                         Bactericides      0.30                                                         Inhibitor from Example                                                                           1.00                                                         11 (with formula VIIa)                                                         Ammonium hydroxide                                                                               2.00                                                         Ammonium chloride 2.00                                                         Lactic acid       5.00                                                         Water             48.50                                                                          100.00                                                       ______________________________________                                     

We claim:
 1. A composition comprising:(i) an elastase inhibitor which is at least one benzisothioazolinone-1-dioxide derivative having the formula: ##STR29## where R¹ is a hydrogen;R² is a group with the formula: ##STR30## and R⁵ is a divalent saturated aliphatic group; and (ii) a pharmaceutically or cosmetically acceptable carrier or vehicle.
 2. A composition according to claim 1, wherein R⁵ is a --(CH₂)₈ -- group. 